I have 256 GB USB sandisk. I cannot copy, delete anything. also cannot format because of the write protection. how to release write protection. there is no switch and no sandisksecureaccess.exe file.
I understand that you are facing Write protection errors, it occurs when a flash drive detects a potential fault within itself. The drive will go into the write-protected mode to prevent data loss. There is no method to fix this.
Please refer: Write Protect Error on USB Flash Drives
We suggest you to please create an Online RMA, here is the link: Online RMA Request